<!DOCTYPE html>
<html lang="en">
<head>
    <meta charset="UTF-8">
    <meta http-equiv="X-UA-Compatible" content="IE=edge">
    <meta name="viewport" content="width=device-width, initial-scale=1.0">
    <title>Document</title>
    <style>
        /* css reset 样式重置 */
        *{
            margin: 0;
            padding: 0;
        }
        body,html{
            height: 100%;
        }
        body{
            /* 手机网页 apple-system */
            font-family: -apple-system-font,sans-serif;
            background-color: #111;
        }
        .page{
            position: absolute; /* 格式化上下文 绝对定位 ，脱离了文档流 */
            top:0;
            right: 0;
            bottom: 0;
            left: 0;
            overflow-y: auto; /* 内部滚动 */
            -webkit-overflow-scrolling: touch; /* 让我们的滚动如丝般顺滑 */
        }
        .page__hd{
            height: 200vh;/* 相对 viewport height单位 视窗*/

        }
    </style>
</head>
<body>
    <div class="page">
        <div class="page__hd">
            <div class="page__title">Flex</div>
            <div class="page__desc">Flex布局</div>
        </div>
        <!-- BEM -->
        <div class="page__bd padding__bd_spacing">
            <!-- weui 项目前缀,组件 新一轮的BEM -->
            <div class="weui-flex">
                <div class="weui-flex__item">
                    <div class="placeholder">weui</div>
                </div>
            </div>
        </div>
    </div>
</body>
</html>